2 Answers
2

What's the best way to learn how to setup OpenVPN?

Read the How To on the OpenVPN website for an introduction, and while configuring OpenVPN, you'll learn by trial and error. I recommend you testing your firewall rules/ routing settings on your home network first, in case anything go wrong and you loose your SSH connectivity, you can always walk to the physical machine and fix it.

The manual page is very useful for getting known with the configuration directives, and explains how custom scripts are evaluated in which order.

(the next setup was intended for a secured Internet connection on a Debian machine / Ubuntu client. Ubuntu is based on Debian, so it works for an Ubuntu server as well)

Ubuntu has a wiki page on setting up OpenVPN for a server+client. I only needed step 1-3 for generating a key, with the custom setup above without using bridges.

What level of proficiency is required in Linux System Administration for this?

Basic knowledge of networking (what layers are, routing) makes you better understand how OpenVPN works. After having set up OpenVPN, you're done. Like any other application, keep your installation up to date (sudo apt-get update && sudo apt-get upgrade) and make sure your keys for using OpenVPN do not get lost.

If you remove the (very good) comments, you are left with around 10 lines of self-explained configuration instructions. There is no easier way if you want to do it alone, on your own server.

As for the second part of the question.
If you are OK with the command line, you have installed one or two other services (like a web server for example), this should be no trouble for you.
Besides, apt does most of the job for you.